This invention relates generally to devices for the measurement of electrical properties of materials, and more particularly to a novel miniaturized test cell for making resistivity measurements and the like on materials in very small sample sizes.
In the measurement of the electrical properties of materials, such as the conductivity, resistivity, dielectric constants, etc., measuring techniques and instrumentation have been well documented in the art.
The use of commercially available electrometers or resistivity cells, however, require that a certain minimum sample quantity is available to prepare samples in appropriate sizes for examination. For example, commercially available resistivity cells ordinarily require a minimum sample size of about ten centimeters in diameter and seven millimeters in thickness, and, further, that the sample exhibit a certain minimum degree of dimensional stability under moderate compression. Use of these measurement instruments is very impractical for small, research size samples, such as fine fibers or thin films. The ability to make desirable measurements on very small samples is therefore limited, which, in turn, limits the capability to make certain measurements on newly developed materials which may be in extremely short supply. Further, the use of new or existing materials in advanced technology applications wherein the materials are configured for use in the form of thin films or fine fibers may require electrical property measurements to characterize these materials as thin films or fibers, which is not feasible in existing instrumentation.
The present invention solves or reduces in critical importance the foregoing problems with existing instrumentation by providing an improved miniaturized test cell for measuring certain electrical properties of samples of very small size. Specifically, the invention comprises a pair of insulated plates appropriately fitted with precisely prepared electrodes for sandwiching a sample therebetween, the assembly being configured to be inserted between the electrodes of a conventional resistivity cell. The invention allows the examination of samples comprising fine (less than about 20 microns diameter) fibers or small (about 6 mm square.times.20 microns thick) thin film specimens, although both thinner and thicker samples could be used.
It is, therefore, a principal object of the present invention to provide an adaptor for accommodating very small sample sizes in resistivity cells.
It is a further object of the invention to provide a miniaturized resistivity cell for use in conjunction with existing instrumentation for electrical property measurement of very small samples.
These and other objects of the present invention will become apparent upon further reading of the detailed description of certain representative embodiments thereof.